Fireproofed cellulosic material

ABSTRACT

FIREPROOFING CELLULOSIC FIBROUS MATERIAL WITH COMPOUNDS HAVING THE FORMULA:   (CH3-NH-)A-P(=O)(-NH2)C(-AZIRIDINE)B   IN WHICH A DENOTES A VALUE FROM 0.1 TO 2.6, B A VALUE FROM 0.3 TO 2 AND C A VALUE FROM 0.1 TO 1.0 THE TOTAL OF A, B AND C BEING 3, AND CELLULOSIC MATERIAL FIREPROOFED THEREWITH.

United States Patent US. Cl. 117-136 4 Claims ABSTRACT OF THE DISCLOSURE Fireproofing cellulosic fibrous material with compounds having the formula:

in which a denotes a value from 0.1 to 2.6, b a value from 0.3 to 2 and c a value from 0.1 to 1.0 the total of a, b and 0 being 3, and cellulosic material fireproofed therewith.

The present invention relates to a process for the fireproofing of cellulosic fibrous material using certain phosphorus amides.

The amides, particularly the dialkylamides and the 1,2- alkylenamides of phosphoric acid are generally known as fireproofing agents for cellulosic fibrous material.

It is possible by means of these agents, which are in general fixed to the fibrous material by heating, to diminish the flammability of the fibrous material considerably, but usually only with impairment of other desirable properties. For example, this treatment may produce embrittlement, a tendency to yellow of textiles finished in this way, and low resistance to washing in the case of some of these prior art fireproofing finishes. This is especially true of the compounds giving the fireproofing effects which have hitherto been the best and most resistant to washing, particularly tris-N-aziridinylphosphine oxide (phosphoric acid trisethylenimide, APO), which has the formula:

CH3 /l N and is very toxic in the unchanged, i.e. unfixed, condition. When using other phosphoric amides (including the non-toxic compound phosphoric-tris-methylamide) good fireproofing effects are obtained, but they are not resistant to washing.

It is known from British patent specification 830,800 that a mixture of approximatelyequal parts of mono ethylenamidophosphoric acid diamide and ammonium chloride may also be used for flameproofing. This substance is however not very suitable for practical use for the reason alone that it contains large amounts of ineffective ammonium chloride which cannot be separated.

The object of the present invention is to provide new and highly effective fireproofing agents for cellulosic fibrous materials which give optimum and wash-resistant fireproofing effects with a minimum of deleterious secondary effects.

We have found that cellulosic fibrous materials can be given a wash-resistant fireproof finish by means of phosphoric amides by applying to the fibrous material ice a composition containing or consisting of a mixture of compounds which is defined by the general Formula I:

in which a may have any value from 0.1 to 2.6, b any value from 0.3 to 2.0 and c any value from 0.1 to 1.0, the total of a, b and c being 3 and the indices corresponding to the average frequency of the methylamido, ethylenamido and amido groups in weighable amounts of the trivalent compound (I).

The mixtures of compounds (I), which are referred to hereinafter as compounds for simplicity, are obtained by conventional methods, preferably by reaction of 1 mole each of phosphorous oxychloride with a moles of methylamide, b moles of ethylenimine and c moles of ammonia in an inert organic solvent at temperatures of from about 40 C. to +40 C. It is recommended that the solvent (for example methylene chloride, benzene, dioxane, tetrahydrofuran or ether) be placed in a reactor and the reactants be passed into the same simultaneously at the same rate in proportion to the molar composition of the product. An appropriate molar excess of a tertiary amine such as trimethylamine or triethylamine should be used to bind hydrogen chloride liberated in the reaction. The hydrochlorides of the tertiary amines are insoluble in the said solvents and can be filtered off therefrom. The solution is then evaporated, advantageously at subatmospheric pressure, after which the product remains as a colorless syrupy liquid. So that it should remain stable for long periods it is advisable to dilute it, for example with dioxane, dimethylformamide or low molecular weight water-soluble alcohols. The mixtures of molecules formed have statistical distribution of the amine radicals on the phosphorus.

By applying to the fibrous material we mean using the fiameproofing mixture by a conventional method or any method which is known in the art.

The new agents are advantageously used in 5 to 50% aqueous solution (percentage here and hereinafter being by weight) for finishing cellulosic fibrous materials, the amount being such that the fibrous material absorbs from about 5 to 50%, preferably from 10 to 30%, of the dry weight of (1) depending on the desired intensity of the fireproofing effect. Application may be for example by dipping, spraying or padding. After the impregnated fibrous material has been dried, the agent is fixed thereon by heating for from about two to twenty minutes at about to 200 0, preferably from to C. Following this, the fibrous material thus finished is given a conventional after-treatment for removal of unfixed agent; for example it may be washed with hot dilute aqueous alkali metal hydroxide solution or alkali metal carbonate solution.

The agents (I) are compatible with all other agents for textile finishing, particularly with a great variety of aminoplast-formin-g monomeric, oligomeric and polymeric compounds and may be used together with them. In other respects, the method according to this invention may be carried out by all procedures and in all apparatus which would otherwise be used for finishing fibrous materials.

Cellulosic fibrous materials may include cotton, linen, sisal, hemp, regenerated cellulose and wood-wool in the form of filaments, threads, fibers, wadding, nonwoven fabrics or sheet materials, such as textiles and papers of all types. These materials may be mixed with others, for example wool, silk, polyester, polyamide or polyacrylonitrile, the total fireproofing effect then corresponding more or less to that of the cellulose fraction.

The invention is further illustrated by the following examples in which the abbreviations used have the same meanings throughout.

EXAMPLE 1 Q amount of compound fixed on the fiber Q amount remaining on the fiber after washing three times with sodium carbonate solution at the boil in accordance with DIN 54,011

B=burning time in seconds after Washing three times at the boil T=tear length in centimeters after washing three times at the boil TABLE 1 Finished with I (a=1.7, b=0.3, Not finished c= 1) Q, percent 16 Q.-, percent 12 B 7-8 The compound (I) is prepared from the appropriate molar amounts providing one mol phosphorus oxychloride, 1.7 mols methylamine, 0.3 mol ethylenimine, one mol ammonia and three moles of triethylamine (as acidbinding agent) in the course of four hours at 10 C. to +20 C. in methylene chloride.

EXAMPLE 2 Cotton twill is impregnated with a 23% aqueous solution of a compound (1 characterized by 11:15, b=1 and c=0.5 so that the amount of finishing agent fixed on the cloth at 150 is about 16% of the dry weight of the cloth. Values for fireproofing and resistance to washing of the finish, determined according to DIN 53,906, are given in Table 2.

TABLE 2 Finished with I (a= 1.5, b=1, Not finished c=0.5

Q, percent 16 Q., percent 12 B Burns through 0 T d0 7-8 The compound (1 is prepared as described in Example 1, like the compound (I but at a mol ratio of one mol of phosphorus oxychloride, 1.5 mols of methylamine, one mole of ethylenimine, and 0.5 mol ammonia.

EXAMPLE 3 A cotton cloth is impregnated with a 23% aqueous solution of a compound (I characterized by a=1, b =1 and 0:1 so that the amount of the finishing agent fixed on the fabric at 140155 C. is about 10-15% of the dry weight of the cloth. The tear length T of the fabric thus finished is 7 to 8 cm. (according to DIN 53,906) after washing three times at the boil (according to DIN 54,011), the burning time 0 sec.

The compound (I is prepared as described in Example 1, like compound (I but at a mol ratio of one mol of phosphorus oxychloride, one mol of methylamine, one mol of ethylenimine, and one mol ammonia.

4 EXAMPLE 4 Cotton cloth is impregnated with a 16% (A), 20% (B) and 23% (C) aqueous solution of a compound (1 (cf. Example 3), condensation being carried out for five minutes at 150 C.

Another sample of the cloth, in a further experiment, is finished in an analogous manner with a 16% (A 20% (B and 23% (Q aqueous solution of the flameproofing agent according to Example 14 of British patent specification 830,800, i.e., a mixture of monoethylenamidophosphoric diamide and ammonium chloride.

Values (determined according to DIN 53,906) for the fireproofing of the finish are given in Table 3.

TABLE 3 T (After wash ing three times T (After with soda at Agent fixation) the boil) Compound (I (according to the invention C 7 1 7 5 Compound according to Example 14 of British patent 830,800:

A 10.2 Burns through. B 9.3 Do. 0 C 8. 0 DO.

The references above to DIN are published German standardized testing procedures used for the purpose of evaluating fire resistance of textiles (DIN 53,906) and as a standardized textile washing procedure (DIN 54,011).

We claim:

1. Fibrous material consisting of or containing cellulose which has been finished with 10 to 30% by weight, based on the cellulose, of a mixture of compounds having the Formula I (NH-CH3);

I //CH2 O:1N I )1) I (NH2) (I) in which a may denote any value from 0.1 to 2.6, b any value from 0.3 to 2 and c any value from 0.1 to 1.0 the total of a, b and 0 being 3 and the indices corresponding to the average frequency of the methylamido, ethylenamido and amido groups in weighable amounts of said compound (I).

2. Fibrous materials as claimed in claim 1 wherein a is 1.7, b is 0.3 and cis 1.

3. Fibrous materials as claimed in claim 1 wherein a is 1.5, b is 1 and c is 0.5.

4. Fibrous materials as claimed in claim 1 wherein each of a, b and c is 1.

References Cited UNITED STATES PATENTS 2,891,877 6/1959 Chance et a1 117136 3,205,034 9/1965 Chance 117--136X 50 3,374,292 3/1968 Zahir 117l36X FOREIGN PATENTS 830.800 3/1960 Great Britain 117136 892,131 3/1962 Great Britain 117136 WILLIAM D. MARTIN, Primary Examiner H. J. GWINNELL, Assistant Examiner US. Cl. X.R, 1l7143, 145, 154 

